Bioreactors are commonly used to culture cells under optimal temperatures and conditions to promote growth. Examples of bioreactors include Xuri™ W5 (GE Healthcare), Xuri™ W25 (GE Healthcare), WAVE Bioreactor™ (GE Healthcare) and stir-tank bioreactors. Liquid growth media is often used to feed the cells by supplying them with nutrients, sugars and growth factors necessary to promote growth, expansion and/or differentiation. As the cells grow and divide they utilise these nutrients and often excrete metabolites which can be toxic to the cells. The used, spent or waste media must therefore be removed and the cells fed with fresh media to continue to promote their growth and expansion.
The removal and/or disposal of this waste media can present problems as it often requires opening the cell culture to decant the waste media thus exposing the culture to potential contamination from airborne microbes. Once collected, the liquid waste must be sterilised, typically by autoclaving, before it can be disposed of. This sterilisation process is time consuming and labour intensive. Alternatively, the liquid waste may be solidified and then disposed of by incineration.
In a typical cell culture system there are three main liquid reservoir components a cell bag in which cells are cultured; a media bag which stores and supplies fresh media into the cell bag; and a waste bag in which used media and waste from the cell bag is collected. The waste bag may need to be detached and replaced several times during the culture process, exposing the cell culture to airborne microbes and risking contamination of the final cell product. This waste is then decanted into a separate container for autoclaving or liquid solidification prior to disposal.
The use of gelling agents to convert liquid waste into solid form for ease of disposal is known in the art. For example, U.S. Pat. No. 5,807,230 discloses waste disposal devices for minimising contamination of an operating room table with blood and body fluid run-off. The bags may contain gelling agents for solidifying the waste material for ease of subsequent disposal.
US2005455972A provides a disposal waste bag containing an absorbent material in a pouch, patch bonded or glued to the bag, or as crystals.
GB2351442A (Smiths Industries Public Limited Company) describes a chest drainage bag with an absorbent material capable of converting the waste flowing from the inlet into a solid. GB2351442A provides an internal member which is a flap extending across the width of the bag, welded at spaced intervals to a wall of the bag. Through the movement of the member in a lever-like motion, liquid travels towards an absorbent material where it is solidified. This member then hinders movement of the solid material back towards the inlet. However, it is cumbersome and expensive to manufacture this chest drainage bag due to the separate welds required to weld the wall to the bag.
EP1736183B1 (VacSax Limited) describes a medical suction disposal system with a flexible body in which liquid from the waste bag of a bioreactor is decanted. The process of decanting into such a system, however, is time consuming and purchasing the system incurs extra cost. Furthermore, the body of this disposal system is not space efficient. However, without VacSax, the waste liquid in the waste bag would need to be autoclaved.
An absorbent material can, additionally, be placed into such a VacSax disposal system in order to solidify the waste before the system is incinerated. Suitable absorbent materials can, for example, be purchased separately from VacSax: (http://www.vacsax.co.uk/index.php/products/-PreGel Gelling Agent) and placed in the system; alternatively the disposal system is also available containing the absorbent material.
In the field of cell culture, there is therefore a need for devices, methods and systems which provide cost-effective and efficient methods for waste collection and disposal which minimise the risk of contamination of the final cell product. The present invention addresses these problems and provides devices, methods and systems which are easy to manufacture and use and further enable collection, solidification and subsequent disposal of waste from a bioreactor.